Purpose: In addition to the eradication of microorganisms in the root canal system, the sealing of the apex is one of the major aims of endodontic treatment. Many studies have illustrated the usefulness of lasers with regard to their bactericidal potential, and the present study was performed to evaluate the sealing ability of different laser systems. Materials and Methods: Eighteen extracted single-rooted teeth were instrumented to a width of ISO 70. Subsequently, dentin powder with a grain size between 6 and 42 Ám was condensed into the apical area of the root canal. Two of these samples were left untreated and served as controls. The remaining 16 teeth were subdivided into 4 groups and underwent laser irradiation using one of 4 different wavelengths (Nd:YAG, diode, Er:YAG, Er,Cr:YSGG) at 2 different settings. After the laser irradiation, the teeth were stained with basic fuchsin solution, sectioned longitudinally with a band saw, and examined under light and scanning electron microscopy. Results: Using light microscopy, the sealing of the apex appeared to be complete in all samples, whereas scanning electron microscopy revealed gaps between the apical plug and the root canal wall in the majority of the samples. Conclusion: The present study opens interesting aspects in the fields of laser-assisted endodontics. Further studies with a larger number of samples have to be conducted to acquire additional information.
Keywords: endodontics, root canal filling, Nd:YAG laser, diode laser, Er:YAG laser, Er,Cr:YSGG laser, scanning electron microscopy, color penetration, apical plug, fusing